Hey Clum -
Something to add to the list when you get back to your punctuation/grammar lessons: the gerund.
I have noticed a spate of that verb form used alone in sentences, which makes them sentence fragments, as there is no active verb anywhere further along in the sentence.
I am looking forward to the primer beginning again.
I never use commas because they slow down the reader. You don't need anything but periods if you are writing well and you don't even need those if you don't want to use them. A friend read one of my stories. Why don't you use any punctuation? she asked me. I told her I was trying to create a sense of immediacy. Starkness. No longer any boundaries between reader and narrator.
Or maybe I'd just been reading too much Cormack McCarthy.
BUMP
Please use commas, but please use them appropriately.
Commas are very important if you want your writing to make sense.
One thing that I didn't see reflected in this thread or the linked article is the inverted relative clause. This is slowly becoming one of my pet peeves.
Inverted Relative Clauses
If you move it to the front of the sentence, a subordinate clause needs to be separated with a comma.
You can see that the sentence above is an example for such an inversion if you look closely. That the sentence starts with a conjunction (if) should already ring a bell. If you encounter a sentence you aren't sure about, take a closer look and determine which part is the main clause and which one is the subordinate clause.
A subordinate clause needs to be separated with a comma. This is our main statement, the rest only refines its meaning and doesn't make much sense on its own.
The natural order of things would be main clause + conjunction + subordinate clause. If we move the main clause to the back, we need a comma.